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Reactions of arylpropargyl amides of fumarate with a base by heating in xylenes under air gave benz[f]isoindolines. Heating the amides of fumarate and ethenetricarboxylate in DMSO gave aroyl-substituted pyrrolidines, probably via addition of water.

We report on the use of anthracene α-diketone as a source of carbon monoxide (CO) in carbonylation reactions. Photoirradiation by a 5 W blue LED of a diyne in the presence of anthracene α-diketone and a rhodium(I) catalyst resulted in a [2+2+1]-carbonylative cycloaddition of the diyne to CO released from the anthracene α-diketone to give a high yield (up to 99%) of the corresponding cyclopentadienone. This is the first demonstration of a CO-gas-free carbonylation reaction using anthracene α-diketone. Light irradiation was a major factor both in the generation of CO from anthracene α-diketone and in the catalytic activity. A halogen lamp, a fluorescent lamp, or sunlight also served as a light source for this reaction. With this system, there is no need for an additional reagent for generating CO.

We report on a series of 1,4-naphthoquinone (NQ)-based photolabile molecules, including various functional compounds to be released under light irradiation. They were efficiently prepared from a common precursor for a photoremovable masking group, by attaching different functional compounds such as alcohols, amines, and acids by a concise synthetic method. Synthesis of the common precursor was optimized for two-step reactions and also for a one-pot reaction involving a 1,4-addition and successive aldol reaction from NQ. The functional compounds, such as alcohols, amines and carboxylic, phosphoric, and sulfonic acids, were masked with the NQ-based precursor and were successfully released by irradiation with UV light (λ = 360 nm) in high yields (>90%).

Time-resolved spectroscopic experiments, assisted with DFT calculations, were employed to study the photochemical reaction mechanism of TC and TS-PPG in different solvents.

Intramolecular cycloaddition reactions of α-bromostyrene-functionalized amides of monomethyl fumarate were investigated. The reaction of the amides with Et

The rhodium(I)-catalyzed reaction of alkynes with aryl­boronic acids in the presence of formaldehyde results in a CO-gas-free arylative dual-carbonylation to produce γ-butenolide derivatives. The simultaneous loading of phosphine-ligated and phosphine-free rhodium(I) complexes is required for efficient catalysis. The former complex catalyzes the abstraction of a carbonyl moiety from formaldehyde through the activation of its formyl C–H bond (decarbonylation) and the latter catalyzes the subsequent dual-incorporation of the resulting carbonyl unit (carbonylation). The use of larger amounts of the phosphine-ligated rhodium(I) complex generates more carbonyl units, leading to the formation γ-butenolides via the dual-incorporation of the carbonyl unit.

Organic azides are still in the center of click chemistry connecting two molecules. However, taming the conjugation selectivity of azides is difficult without the help of bulky groups. We report herein the unique reactivities of α-azido secondary acetamides (α-AzSAs) as minimal and unhindered azide structures. The NH–azide interaction in the α-AzSAs, supposed by DFT calculations, allowed selective conjugation in the presence of other azido moieties, even without steric hindrance. With Staudinger–Bertozzi ligation, α-AzSAs underwent conjugation prior to the other primary alkyl azides. On the other hand, in propargyl cation-mediated triazole synthesis, other alkyl azides, including tertiary alkyl azides, underwent the conjugation faster than α-AzSAs. We also demonstrated site-selective integration of the functional components onto the diazide modular hubs.

Inter- and intramolecular cycloaddition reactions of ethenetricarboxylates with styrenes and α-halostyrenes have been investigated. The reactions of ethenetricarboxylates with styrenes or α-bromostyrenes in the presence of SnCl4 or SnBr4 stereoselectively gave 2,4-cis-substituted cyclobutanes. The intramolecular cycloaddition reactions of a series of styrene-functionalized ethenetricarboxylate amides, including in situ generated derivatives, showed high diversity of reaction modes depending on the structures and substituents of the substrates. The regioselectivity and stereoselectivity of the reactions as well as reaction mechanisms were discussed based on the DFT calculations.

We describe transfer carbonylation reactions of 2-bromoarenes that contain a carbon-nucleophile using aldehydes as a substitute for CO, leading to the formation of indanone derivatives. The transformation proceeds efficiently under RhI /Pd0 -hybrid catalytic conditions consisting of two discrete transition metals, rhodium and palladium, which catalyze the decarbonylation of aldehydes and the subsequent carbonylation of bromoarenes using the resulting carbonyl moiety, respectively. The majority of the abstracted CO is transferred directly to the product via a CO-relay process from rhodium to palladium.

We report herein the unique reactivities of α-azido secondary acetamides (α-AzSAs) as minimal and unhindered azide structures. The NH–azide interaction in the α-AzSAs, supposed by DFT calculation, allowed selective conjugation in the presence of other azido moieties. With Staudinger-Bertozzi ligation, α-AzSAs proceeded the conjugation prior to the other primary alkyl azides. On the other hand, in propargyl cation-mediated triazole synthesis, other alkyl azides, including tertiary alkyl azides, underwent the conjugation faster than α-AzSAs. We also demonstrated discriminative integration of the functional components onto the diazide modular hubs.

We report herein the unique reactivities of α-azido secondary acetamides (α-AzSAs) as minimal and unhindered azide structures. The NH–azide interaction in the α-AzSAs, supposed by DFT calculation, allowed selective conjugation in the presence of other azido moieties. With Staudinger-Bertozzi ligation, α-AzSAs proceeded the conjugation prior to the other primary alkyl azides. On the other hand, in propargyl cation-mediated triazole synthesis, other alkyl azides, including tertiary alkyl azides, underwent the conjugation faster than α-AzSAs. We also demonstrated discriminative integration of the functional components onto the diazide modular hubs.

In this work, the [2+2] photocycloaddition of carbonyl compounds with olefins, the Paterno-Buchi-type photoreaction, was performed in a flow microreactor under slug flow (two-phase flow) conditions...

This paper reports the selective conversion of alkyl azido groups at the carbonyl α-position into oximes through β-elimination of dinitrogen, followed by transoximation. With this method and diazo conversion, a triazido molecule was transformed into a triple click conjugation scaffold allowing one-pot four-component coupling.

We describe the effective rhodium(I)-catalyzed [2+2+1] carbonylative cycloaddition of diynes, yielding cyclopentadienes (CPDs), under photoirradiation. The catalysis involves the promotion of the photodissociation of the product CPD, with the simultaneous production of an essential vacant coordination site on the rhodium for an unreacted substrate. The combined use of cationic [Rh(cod)2]BF4 as a catalyst and photoirradiation was also found to give various CPDs in high yields (≤96%).

Schmidt reaction by sulfonium ions is described. General primary, secondary, and tertiary alkyl azides were converted to the corresponding carbonyl or imine compounds without any trace of the activators. This bond scission reaction showcased ring-opening, -expansion, and one-pot further conversion of the substrates as well as the application with C-H azidation.

The synthesis and characterization of a 'complete set' of positional isomers of tetrakis(perfluorophenyl)porphyrins (TFPP)-glucose conjugates (1OH, 2OH, 3OH, 4OH, and 6OH) are reported herein. The cellular uptake and photocytotoxicity of these conjugates were examined in order to investigate the influence of location of the TFPP moiety on the d-glucose molecule on the biological activity of the conjugates. An In vitro biological evaluation revealed that the certain of these isomers have a greater effect on cellular uptake and cytotoxicity than others. The TFPP-glucose conjugates 1OH, 3OH, and 4OH were found to exert exceptional photocytotoxicity in several types of cancer cells compared to 2OH and 6OH substituted isomers.

Nitrosoallene-mediated endo-dig cyclization reactions producing (hetero)cyclic exo-unsaturated oximes (enoximes) are described. The intramolecular 1,4-type addition to in situ generated nitrosoallenes afforded α-substituted cyclic enoximes with exo-methylene units, which are the favored conformation for further cyclizations. The strong electron-withdrawing ability of the nitroso group facilitated the construction of five-to-seven-membered ring systems via C-O, C-N, C-S, and C-C bond formations, including a quaternary carbon center, at low temperatures.

In spite of the significant progress made in transformations of unstrained benzylic (tert-)alcohols through β-aryl elimination, catalytic carbonylation has not yet been developed extensively because alkoxycarbonylation is probably favored over β-aryl elimination. In this letter, we report on the rhodium(I)-catalyzed carbonylative annulation of α,α-dimethyl-(2-bromoaryl)methanols with internal alkynes using furfural leading to the formation of indenones. The key to the success of the reaction is the timely generation of the carbonyl source via the decarbonylation of furfural.

The rhodium(I)-catalyzed carbonylative annulation of iodobenzenes with strained olefins in the presence of furfural as a carbonyl source, accompanied by ortho-C–H bond cleavage, is reported. The use of 4-octyne in place of strained olefins also leads to the formation of the corresponding inden-9-one. The timely release of the carbonyl moiety via the rhodium-catalyzed decarbonylation of furfural plays a decisive role in this reaction.

We herein describe the syntheses and characterization of extended germa[N]pericyclynes, which are macrocycles composed of germanium-butadiyne units. The obtained novel extended germa[4]-[8]pericyclynes were characterized by X-ray crystallography, UV-Vis spectroscopy, fluorescence and phosphorescence emission spectroscopy, and cyclic voltammetry, and exhibited characteristic absorptions and emissions. Density functional theory (DFT) calculations suggested smaller HOMO-LUMO gap energy compared to that of general germapericyclynes.

We previously showed that curcumin, a phytopolyphenol found in turmeric (Curcuma longa), targets a series of enzymes in the ROS metabolic pathway, induces irreversible growth arrest, and causes apoptosis. In this study, we tested Pentagamavunon-1 (PGV-1), a molecule related to curcumin, for its inhibitory activity on tumor cells in vitro and in vivo. PGV-1 exhibited 60 times lower GI50 compared to that of curcumin in K562 cells, and inhibited the proliferation of cell lines derived from leukemia, breast adenocarcinoma, cervical cancer, uterine cancer, and pancreatic cancer. The inhibition of growth by PGV-1 remained after its removal from the medium, which suggests that PGV-1 irreversibly prevents proliferation. PGV-1 specifically induced prometaphase arrest in the M phase of the cell cycle, and efficiently induced cell senescence and cell death by increasing intracellular ROS levels through inhibition of ROS-metabolic enzymes. In a xenograft mouse model, PGV-1 had marked anti-tumor activity with little side effects by oral administration, whereas curcumin rarely inhibited tumor formation by this administration. Therefore, PGV-1 is a potential therapeutic to induce tumor cell apoptosis with few side effects and low risk of relapse.

In this study, novel caged antisense oligonucleotides with thiochromone S,S-dioxide as the photolabile protecting group were synthesized, and their photodeprotection was investigated. In vitro experiment, the original target molecule was successfully recovered by photoirradiation. Furthermore, the photodeprotection process was also successfully monitored by the fluorescence spectroscopy of highly fluorescent byproducts generated from the thiochromone-type photolabile protecting group.

A new and efficient thiochromenone S , S -dioxide-based photolabile protecting group for propargylic alcohols is described. Robust protection reactions were developed through copper (II)-catalyzed substitution of propargylic alcohols. Subsequent photodeprotection proceeded smoothly to give the corresponding propargylic alcohols quantitatively within 15 minutes, as demonstrated by 1 H NMR spectroscopy and HPLC. Notably, the photoproduct derived from the thiochromenone derivatives showed a high fluorescence quantum yield, permitting monitoring of the reaction progress by fluorescence spectroscopy. A new strategy for the synthesis of triazoles by a one-pot reaction is also presented.

A typical (Paterno-Buchi type) organic photoreaction is examined in flow microreactors. Compared to the results achieved for simple one-layer flow modes, slug flow conditions (with the unreactive reagent composed of organic solution and water) achieve higher efficiency (conversion and yield) irrespective of the light source, concentration, and solvent. Furthermore, remarkably high productivity is also observed when only 5% water is added as an unreactive reagent. This method is broadly applicable for achieving highly efficient organic photoreactions not only in the laboratory, but also on the industrial scale.

A dual neutral-cationic rhodium(I)-catalyzed Pauson–Khand-type reaction using formaldehyde as a carbonyl source is described. The simultaneous use of neutral rhodium(I) and cationic rhodium(I) complexes is required for efficient cooperative catalysis, which involves the neutral rhodium(I)-catalyzed decarbonylation of formaldehyde and the cationic rhodium(I)-catalyzed cyclocarbonylation of 1,6-enynes using the resulting carbonyl moiety.

This paper presents the synthesis and characterization of (TMS-ethynyl)-substituted germa[4]pericyclyne composed of acetylene moieties and germanium atoms. Characterization was performed by X-ray crystallography, UV–vis absorption, and photoluminescence spectroscopy. DFT calculations suggested interactions between the side chain alkynes and the ring-forming acetylenes through germanium vertex atoms.

Paraformaldehyde serves as a carbonyl source in the Pd-catalyzed cyclocarbonylation of 2-bromobiphenyls through the cleavage of a C–H bond to afford good yields of fluoren-9-one derivatives. This p...

The diastereodifferentiating [2+2] photocycloaddition of a chiral cyclohexenone with cyclopentene was performed in supercritical carbon dioxide (scCO2) using a flow microreactor. In all cases examined, the microreactor gave higher conversions than the batch system because of the very short path length of the microreactor. Additionally, by using the microreactor, accurate temperature control produced higher diastereoselectivity. These distinguished findings can be attributed to the synergistic effect of superior light penetration in the microreactor and the unique solvent property (clustering effect) of scCO2.

We describe the full details of multicomponent coupling reactions in acid-mediated synthesis of fully substituted 1,2,3-triazoles syntheses, and their applications to bioactive molecule synthesis. For substitution with wide range of nucleophiles, selection of acids or activating reagents was important, and various types of multicomponent coupling reactions were demonstrated, allowing functionalization with alcohols, amines, thiol, azide, and carbon nucleophiles. Four-component couplings including double triazolations were also tested. The efficiency of this method was demonstrated by the synthesis of serine hydrolase inhibitor and its novel substituted derivatives.

Total synthesis of α,β-, and α,β,γ,δ-unsaturated imine ant venom alkaloids is described. The labile two conjugated imine alkaloids were synthesized by late stage intramolecular Schmidt reaction via allyl and pentadienyl cation intermediates.

A new caged firefly luciferin (luciferin) with a thiochromone S , S -dioxide (TSSDO) as a photolabile protecting group was synthesized. Photodeprotection of the caged compound proceeded smoothly under photoirradiation at 365 nm in aqueous solution. The bioluminescence of the regenerated luciferin after uncaging was detected using a typical luciferin–luciferase reaction. These results indicated that TSSDO could be an attractive chemical tool for regulating biological phenomena.

The rhodium(I)-catalyzed reaction of alkynes with arylboronic acids in the presence of formaldehyde resulted in a carbon monoxide gas-free carbonylative arylation to yield α,β-enones. The simultaneous loading of phosphine-ligated and phosphine-free rhodium(I) complexes is required for efficient catalysis, which catalyze the abstraction of a carbonyl moiety from formaldehyde (decarbonylation) and its subsequent introduction into the substrate (carbonylation), respectively., Ministry of Education, Culture, Sports, Science and Technology, Japan

Enantiodifferentiating [2+2] photocycloaddition of cyclohexenone carboxylic acid with the smallest olefin, ethylene, was accomplished using 8-phenylmenthyl amine as a chiral template. Particularly, we succeeded in enhancing the enantiomeric excess (ee) value by selective excitation of a chiral substrate–template supramolecular complex.

The synthesis and characterization of novel pericyclynes comprising germanium atoms and acetylenes, germa[n]pericyclynes, are described. The prepared germa[4]-, [6]-, and [8]pericyclynes were compared by (13)C NMR spectroscopy, X-ray crystallography, cyclic voltammetry, UV-visible spectroscopy, fluorescence emission spectroscopy, Raman spectroscopy, and density functional theory calculation analyses.

In this paper, we report the design and moleculardocking study of analogues of antimycin A3 as inhibitors of anti-apoptotic Bcl-2 of breast cancer. Twenty designed compounds and the original antimycin A3 were docked based on their interaction with breast tumor receptor binding target Bcl-2. The docking resulted in the five top-ranked compounds, namely, compounds 11, 14, 15, 16, and 20, which have a lower G binding energy, better affinity and stronger hydrogen bonding interactions to the active site of Bcl-2 than antimycin A3. Among those five top-ranked compounds, analogue compounds 11 and 14, which have an 18-membered tetralactone core and 18-membered tetraol core, respectively, exhibited the strongest hydrogen bond interaction, formed high stability conformation, and demonstrated the greatest inhibitory activity on the catalytic site of Bcl-2.

A novel photolabile protecting group, thiochromone S,S-dioxide, possessing the 1,2-diol group for protection of ketones and aldehydes is described. Photodeprotection of the successfully protected carbonyl derivatives proceeded smoothly under photoirradiation filtered through Pyrex glass (>280 nm) using an ultrahigh-pressure mercury lamp to recover the corresponding carbonyl compounds and the starting protecting group.

X-ray crystallographic analysis revealed that the palladium-catalyzed β-allylation of yohimbine proceeded in a (7S)-selective manner. The crystal structure had an indolenine unit that was generally unstable in air. A stereoselective outcome was obtained when the palladium π-allyl complex approached yohimbine from the less-hindered pro-S side. However, during reserpine allylation—because the structure of reserpine is that of a transoid-3, 15-ring junction—the palladium π-allyl complex approached from both sides: pro-S and pro-R. A computational method was developed to discuss this selectivity. Experimental details and considerations of the reaction are provided.

We conducted diastereodifferentiating [2+2] photocycloadditions of cyclo-hexenones modified with a chiral 8-(p-methoxy phenyl)menthyl auxiliary with olefins in water. Although the photoreaction didn't proceed at all in pure water owing to very low solubility, the use of surfactants [sodium dodecyl sulfate (SDS) or dodecylamine hydrochloride (DAH)] and additive (organic solvent) enabled the reactions to progress with moderate to high conversions and yields. Furthermore, we synthesized a new menthol derivative substrate containing a (p-octyloxy)phenyl group for enhancing hydrophobicity, and elucidated that this new substrate was found to be a suitable chiral auxiliary in this asymmetric photoreaction in aqueous system. The additive effect of organic molecules on the yield and diastereoselectivity of the photo-adducts is also discussed.